It was supposed to bring constitutional chaos and the destruction of the United Kingdom as we know it - but as the Scottish National party government nears its 100th day in office, it's been consensus, not chaos, that has characterised Alex Salmond's premiership north of the border. Even yesterday's launch of the SNP's white paper on independence has provoked at least some measure of agreement between Scotland's parties - something unthinkable just a few months ago. All now accept that, at the very least, a debate needs to be held on the transfer of more powers from Westminster to Edinburgh - a position that we are told is approved by both Gordon Brown and David Cameron.

Although the online version of the independence document is accompanied by the stirring rhetoric of the 19th century Irish nationalist leader Charles Stewart Parnell, in truth the Scottish National party does not want an all-out pitched battle over the constitution. Instead, the party is concentrating on two things - demonstrating that it can govern with principled competence and building national coalitions around campaigns to beef up the powers of the Scottish parliament.

On the first point, the new administration has proved so skilful that Labour, in particular, appears bewildered - so much so that the former first minister, Jack McConnell, is widely expected to announce his resignation shortly, to be replaced by Wendy Alexander (a daughter of the manse, meaning Labour in the UK and Scotland will have the Church of Scotland to thank for its leadership).

Under McConnell Labour has failed to respond meaningfully to popular government initiatives, such as halting the closure of local A&E facilities, ending bridge tolls, measures to cut class sizes in primary schools, and an energy policy that rules out new nuclear power stations.

The Scottish press, so long antagonistic towards Salmond, has now fallen head over heels in love with the new first minister, who currently dominates the country's politics. The Queen has been charmed, the prime minister is referred to in first-name terms (as opposed to his predecessor, whom Salmond repeatedly called a liar), and the SNP leader has even agreed to become a privy counsellor.

None of this means the SNP is moving away from independence. Far from it. Governing well is worth more than a hundred slogans about freedom because it removes for ever the previously powerful unionist charge that the advocates of independence are inexperienced, with no record of taking decisions, and consequently represent a massive leap into the unknown.

The SNP has also been choosing its constitutional ground carefully. Tapping into widespread sentiment in Scotland that the BBC is in fact the English Broadcasting Corporation - or perhaps more accurately the London Broadcasting Corporation - Salmond last week raised the issue of whether powers over Scottish broadcasting should be a Holyrood and not a Westminster responsibility. In a typically astute turn of phrase, referring to the famous statement by the former director general Greg Dyke about the ethnic make-up of the BBC, the corporation was accused of being hideously White City.

Next on the list is likely to be tax powers. In an indication of the changing political weather in Scotland, this is not about seeking powers in order to tax to the hilt the financial fat cats of Edinburgh's Charlotte Square. The idea is to use the business tax system to create a competitive environment for inward and local investors. On both these issues - broadcasting and tax - the SNP is reaching out beyond its traditional support to make the case for constitutional change.

Tellingly, the SNP leadership was nowhere near a summer row over whether the union flag or the saltire should be flown highest over Edinburgh Castle. It has more substantial matters to consider.

All of this should alarm Brown - who is enjoying his own extended political honeymoon. In the short term, the popularity of the SNP will be a key factor in determining whether or not to call an early general election. The prime minister will be acutely aware of the seats lost by Labour in major cities such as Dundee, Edinburgh and Glasgow in the Scottish parliament elections. Hoping that Labour voters will "come home" for a Westminster election in a matter of months appears a real gamble.

In the longer term, a coalition of civic Scotland around the demand for greater powers for the Scottish parliament could form the basis for a powerful independence campaign - something that Brown has devoted much of his political life to stopping.

· Ewan Crawford was private secretary to John Swinney, the former leader of the SNP, from 2001 to 2004